This Core resource will provide comprehensive biostatistics and bioinformatics consultation and collaboration to all projects in the proposed Johns Hopkins Breast SPORE. In addition, it will provide support for data storage, informatics, and computing, and assist with the identification and solution of complex data tasks arising in the course of project activities. Core members will work with project investigators across a wide spectrum of activities, encompassing data acquisition (including study design, feasibility of objectives, availability of public-access genomic information, and data storage), statistical quality control (including artifact detection and preprocessing of data from genomic technologies), data analysis (including visualization, biostatistical modeling, and assistance with manuscript writing), and development of innovative customized biostatistics and bioinformatics methodologies and tools if required by specific projects. The Breast SPORE Biostatistics and Bioinformatics Core is housed in the Division of Clinical Trials and Biometry of the Department of Oncology, an active and committed group of biostatistics and bioinformatics faculty members, with access to state-of-the art equipment and a broad range of expertise. This Core resource is the continuation of an existing resource within the original and current Breast SPORE program at Johns Hopkins. Core members have a strong commitment to this SPORE, stemming from: a) a history of collaboration with the investigators of this as well as other SPORE projects b) an active and independently funded agenda of synergistic progects in cancer genetics and genomics, with substantial breast cancer components and c) a demonstrated interest and understanding of both the biological and analytical questions and challenges. All proposed projects are anticipated to make use of this resource in every aim.